Nordiazepam → Pinazepam

Participants

Reaction Steps

100 ml. of a 1 N solution in sodium methoxide in methanol were added to a solution of 27.05 g (0.1 mol) of 7-chloro-2,3-dihydro-5-phenyl-1H-1,4-benzodiazepin-2-one in 500 ml. of anhydrous methanol. The solvent was driven off under reduced pressure, and the resulting sodium derivative was dissolved in 200 ml. of dimethylformamide. The temperature of the solution was maintained at 10°-15° C. while 10 ml. of propargyl bromide were added dropwise; and the mixture was stirred for about 4 hours, and then poured over ice. The product was filtered and dissolved in chloroform; and the chloroform solution was separated from the aqueous layer and dried over sodium sulphate. The chloroform was evaporated off from the solution, and the residue was dissolved in the minimum quantity of a 7:3 (by volume) mixture of benzene and ethyl acetate. This solution was chromatographed on a column of silica gel and eluted with a 7:3 (by volume) mixture of benzene and ethyl acetate. The portion of eluate containing the desired product, as determined by thin-layer chromatography, was collected and evaporated under reduced pressure. The residue was recrystallized from a 1:1 (by volume) mixture of benzene and hexane, giving 14 g of the pure desired product with a melting point of 141°-143° C.

Provenance & Evidence